<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>visibility</title>
    <style>
        div{
            height: 200px;
            width: 200px;
        }
        .a{
            background-color: gray;
            visibility: hidden;
            /* 隐藏但还是占有原来的位置 */
        }
        .b{
            background-color: red;
        }
    </style>
</head>
<body>
    <div class="a"></div>
    <div class="b"></div>
</body>
</html>